refactor(stm): Reuse the cached unsafe SRS in the SNARK test setups

[damrobi]

Content

This PR includes an update to the way we use the unsafe SNARK setup in tests in order to reduce the runtime of the tests.

Gain in test time

Baseline: 1h11m47s (nightly 30/07 https://github.com/IntersectMBO/mithril/actions/runs/30506077425/job/90756011560)

After commit 1: 1h00m56s (https://github.com/IntersectMBO/mithril/actions/runs/30538872179/job/90858636858)

After commit 2: 40m50s (https://github.com/IntersectMBO/mithril/actions/runs/30552401815/job/90904114168?pr=3443)

After commit 3: 58m08s (https://github.com/IntersectMBO/mithril/actions/runs/30559800977/job/90929571831?pr=3443)

• Regression potentially due to new tests taking all threads instead of using a single thread

Pre-submit checklist

• Branch
  • Tests are provided (if possible)
  • Crates versions are updated (if relevant)
  • CHANGELOG file is updated (if relevant)
  • Commit sequence broadly makes sense
  • Key commits have useful messages
• PR
  • All check jobs of the CI have succeeded
  • Self-reviewed the diff
  • Useful pull request description
  • Reviewer requested

Comments

Issue(s)

Closes #3433

[github-actions]

Test Results

     5 files  ± 0     209 suites  ±0   2h 35m 53s ⏱️ + 1h 33m 55s
 3 413 tests +83   3 411 ✅ +81  0 💤 ±0  2 ❌ +2 
11 182 runs  +92  11 180 ✅ +90  0 💤 ±0  2 ❌ +2 

For more details on these failures, see this check.

Results for commit e59acd2. ± Comparison against base commit 23e124d.

♻️ This comment has been updated with latest results.